The present disclosure relates to an opto-electrical transceiver module, in particular to a header or receptacle module for connecting an active optical cable to a host device. The present disclosure also relates to an active optical cable provided with such an opto-electrical transceiver module.
Active optical cables use electrical-to-optical signal conversion on the cable ends to provide high-speed signal transmission, e.g., up to 10 Gbits/s or faster, without sacrificing compatibility with standard electrical interfaces. The terminal ends of active optical cables are provided with opto-electrical modules for converting electrical signals into optical signals and vice versa. Active optical cables can replace conventional copper cables allowing longer cable lengths at higher data transmission rates.
An opto-electrical transceiver module usually includes a transmitter unit for transmitting optical signals and a receiver unit for receiving optical signals.
The transmitter unit is typically provided with electrical driver circuitry, one or more high speed light sources, such as one or more lasers and/or one or more LED's, and an optical coupling unit for guiding optical signals from the light sources to an optical waveguide, in particular optical fiber.
The receiver unit is typically provided with an optical coupling unit for receiving optical signals from optical waveguides, in particular optical fibers, photoelectric elements for converting the optical signals to electrical signals, such as PIN or APD diodes, and amplifier circuitry to amplify signals to a suitable logical output signal level.
Additionally a microcontroller can be used to control and monitor the receiver unit and/or the transmitter unit and/or to provide access to these units via a low speed interface. Such a microcontroller can also be used to store non-volatile settings and/or product related information in its memory accessible via a low speed interface.
These components are usually carried on one or more printed circuit boards (PCB's) with contact pads for contacting matching data transmission contacts of a host device. There are several possible standard configurations. In one of these standard configurations a stack of two PCB's is used: a transmitter PCB with contact pads for receiving electrical signals from the host device and a receiver PCB with contact pads for transferring electrical signals to the host device. In present day transceiver modules the transmitter PCB carries the transmitter chip and associated components including an optical coupler for guiding outgoing optical signals from the light sources to waveguides of an optical cable, while the receiver PCB carries the receiver chip and associated components including an optical coupler for guiding incoming optical signals from optical waveguides of an optical cable.
In use optical signals coming in from optical waveguides of an optical cable are converted by the receiver unit into electrical signals traveling on the PCB to the host device, into which the opto-electrical transceiver module is plugged. In return, incoming electrical signals from the host device travel via the transmitter PCB to the driver circuitry driving the high speed light sources to convert the electrical signals to optical signals. These optical signals are fed to optical waveguides of an optical cable via the optical coupling unit.
The receiver and transmitter units and PCB's consume considerable space resulting in bulky modules. In line with the general trend of miniaturization there is a need for an opto-electrical module consuming less space. More particularly, many host devices have a communication port configured to communicate with Mini SAS HD standard interface connectors, which creates a need for an optical transceiver module that is compact enough to be designed as a Mini SAS HD module.